Apparatus for the production of music



June 29, 1943.

B. F. MIESSNER 2,323,232

APPARATUS FOR THE PRODUCTION OF MUSIC Filed May 14, 1940 2 Sheets-Sheet2 CURRENT 68w SOUR: L 65 86 87 e1 64 614 I 400 7 Ii-ml 94 95 3nnentorPatented June 29, 1943 APPARATUS FOR THE PRODUCTION OF MUSIC Benjamin F.Miessner, Harding Township, Morris County, N. .L, assignor to MiessnerInventions, Inc., Harding Township, Morris County, N. J.,' a corporationof New Jersey Application May 14, 1940, Serial N0. 335,064

16 Claims.

This invention relates to the production of music, and in itsprincipalaspects to that pro! duction involving the translation of soundfrom sound-representing electric oscillations. Important aspects of theinvention involve the production of the sound-representing electricoscillations by translation from the vibrations of tuned vibrators, andmore specific aspects involve such translation from the strings of aninstrument of the piano type. The invention has been specificallyillustrated and described in connection with an instrument of the lattertype, but it will be understood that in broader aspects no unnecessarylimitation thereto is intended.

It is an object of the invention to provide improved and simplifiedarrangements for the translation of electric oscillations from thevibrations of tuned vibrators.

It is an object of the invention to provide improved arrangements of thetype above described, operating magnetically.

It is an object to provide improved arrangements of the typeabovementioned which may be effectively used to modulate high-frequencycurrents at the vibrational frequencies.

It is an object to provide, in association with arrangements suchasabovementioned, appropriate means for controlling the envelopes, oramplitude-time characteristics, of the output tones.

It is an object to provide, in an electronic instrument of the pianotype, an improved arrangement of sound-radiating means with respect tothe other portions of the instrument.

Other and allied objects will more fully appear from the followingdescription and the appended claims.

In the description of the invention hereinafter set forth, reference ishad to the accompanying drawings, of which:

Figure l is a front elevational view of an electronic piano in which myinvention has been embodied in one form, most of the front cover memberand most of the action being removed for the better illustration ofparts therebehind;

Figure 2 is a rear elevational view of the instrument of Figure l;

Figure 3 is a fractional cross-sectional view,

taken along the line 3-3 of Figure 1;

Figure 4 is a fractional cross-sectional view, taken along the line 4-4of Figure 3, together with a schematic illustration of circuitcomponents;

v Figure 5 is a partial plan view of an electronic instrument of thegrand-piano type in which my invention has been embodied in anotherform, together. with a schematic illustration of certain circuitcomponents; and

Figure 6 is a partial cross-sectional view taken along the line 6-4 ofFigure 5, together with a schematic illustration of other circuitcomponents.

An embodiment of my invention has been illustrated in Figures 1, 2, 3and 4, the latter two figures being enlarged cross-sectional views ofrestricted portions of the former. Figures 1 and 2 illustrate aninstrument of the piano type, which in its general constructionotherthan that immediately involved in the translation of the stringvibrations into electric oscillations may for example be similar to thatillustrated and described in Patent No. 2,200,718 to me, to which patentreference may be had for details not in themselves necessary to mentionin the following brief description of that general construction.

In Figures 1 and 2 will be seen a vertical, rectangular metallic frameor plate I serving as a basis to which the other components may bedirectly or indirectly assembled. This plate is conveniently providedaround its periphery with the forwardly extending flange 2. The centralportions of the plate are apertured; but the plate is reinforced bycross-webs such as 3, some of these being in turn reinforced withforwardly extending flanges such as 4. To the back of the plate may besecured a peripheral framework, comprising for example the wrest-plank 5across the top, the wooden cross-member 6 across the bottom, and thevertical wooden end members i. To the plate I, through the medium ofthis framework, may be supported a vibratile system comprising certainbridges (hereinafter described) and a plurality of vibratile ribs 8thetops of the ribs being secured in the wrest-plank 5, the bottoms of theribs being secured in the cross-member 6, and the ribs being preferablyslightly bowed forwardly in their central portions. Forwardly andbackwardly extending vertical standards 9 may be secured to'the two endsof the plate I to form a support therefor and, if desired, to form theexposed ends of the only appear in Figure 1, adjacent the, respectivevertical end standards 9). The illustration of ribs 2 has been omittedfrom Figurel in the interest of clarity of showing.

The top portion of the plate I is suitably apertured to permit aplurality of tuning pins II to extend forwardly therethrough fromwrest-plank I, wherein they are secured. From these pins to hitch p nsII in lower portions of the plate i extend the several tuned strings ofthe instrument, of which the upper trebl strings are indicated as It,the lower treble strings as II, and the bass strings as l4--it beingunderstood that each of these groups of strings is only fractionallyshown in the interest of simplicity of the draw n sv All the treblestrin s have been shown as passing from the tuning pins l2 under apressure bar If and over a ledge l2 defining the upper extremities oftheir activ portions; the bass strings II. which may be overstrung (i.e.. disposed slightly in from; of and somewhat transversely to thetreble strings), may pass around respective localizin pins Iii in thedefin ng ledge II. The bridges over which the strings pass, and whichdefine the lower extremities of the active string portions. arehereinafter described.

For vibrating the strings there may be employed, for example, theimpulse or striking excitation usual to the piano, typically by means ofthe usual piano hammer, damper and pedal action; this has been indicatedin Figure 1 as including the keys 20 and pedals 2i and 22, and has beendesignated generally as A. It may for example be of the "dropped"typedetails of which, over and above the quite fractional showing ofFigure 1, have been illustrated and more fully described in the PatentNo. 2,200,718 abovementioned. While no particular limitation is intendedas to the number of strings per note, I have in Figures 1 and 2illustrated the use of two strings per note throughout the principalporti of the scale.

The bridges over which the strings pass are shown as 4! and 43 for thetreble and bass strings, respectively. These extend transversely of, andare secured to, the ribs 8. The bridge 4i has been illustrated asprovided with a portion 42 of reduced thickness extending underneath (i.e., behind) the active string portions (1. e., upwardly), and the bridge42 with a corresponding extending portion 44. These portions form a convenient, though non-limitative, support for the mechanico-electrictranslating apparatus shown in this embodiment of my invention.

In carrying out my invention I cause the strings to have magnetic fieldswhich intersect a conductive circuit and which, when the strings arevibrated, oscillatorily infiuence that circuit to createvibration-representing electric oscillations therein. According to animportant aspect of the nvention, I arrange the conductive circuit for aplurality of different-frequency strings as a single one, extendingtransversely of the strings and having portion adjacent thereto to beoscillatorily approached and receded from by the strings during theirvibrations.

Such a circuit has been embodied in the construction of Figures 1through 4 as a single-tum loop for all the treble strings, together withanother single-turn loop for all the bass strings. One side of the loopis in close spaced relationship to the strings--typically at a spacingtherefrom not greatly in excess of that required to. avoid its beingstruck by the strings under condit ons of their maximum-amplitudevibrations. It is on this side of the loop that the string vibrationshave their significant and intended infiuence. The other, or "return,side of the loop i kept at a much larger distance from the strings,whose vibrations accordingly have negligible effect on it-whlch isdesirable, since the latter influence tends to oppose the former withinthe loop circuit. The loop for all the treble strings has beenspecifically illustrated as a heavy conductor 50, typically thoughnon-limitatively of rectangular cross-section. The active side Ila ofthe loop i disposed behind the strings, preferably opposite longitudinalportions thereof which vibrate with the most desirable harmonicdevelopment; and since these portions may typically be portionsrelatively near th bridge extremities of the strings, the loop side amay conveniently be secured to the portion 42 of the bridgeabovementioned. This securing has been shown by way of preferred exampleas carried out through the medium of screws II passing rearwardlythrough the conductor ill and into the bridge portion 42,

Between the conductor 50 and the bridge portion 42 there may be providedabout the screws ll respective expansion springs 52, which urge theconductor forwardly against the heads of the screws 5|; this renders theturning of each screw effective to adjust the precise spacing of theconductor, in the region of that screw, from the strings. Several of thscrews Il may be employed at intervals along the conductor 50, and thelatter may be made of a relatively soft metal to respond in its severalportions to adjustment by the respective screws. Since the degree ofinfluence of the vibrating strings on the loop will be directly affectedby the spacing of loop from string, the voicing of the instrument as torelative outputs in different scale portions may be very preciselyadjusted by means of the screws ll.

At the extremities of the bridge 4i the conductor I0 may be foldedaround the end of the bridge portion 42 (as appears for the extremetreble extremity in Figure 4) to form the second or return side lllb ofthe loop; this may conveniently be secured to the backs of the ribs 8,for example. At a convenient point in the loop side b the loop isprovided with a discontinuity, formed between spaced extremities 500 ofthe otherwise continuous conductor. The loop circuit is closed byconnection across these extremities of a very low impedance primary 50aof a transformer l4.

Because of the overstrung arrangement of the bass strings in theparticularly illustrated instrument construction, it may be relativelydifflcult to extend the one loop 50 into an effective relationship tothe bass as well as to the treble strings; accordingly I have preferredto employ for these strings, as indicated in Figures 1 and 2, a separateloop 53 related to them in an analagous manner to that described forloop 50 and the treble strings. While this loop 52 may be connected inany of a variety of ways to merge its output with that from the loopIII, I have by way of example indicated in Figure 4 the provision of aseparate transformer 81 to the primary I'Ia of which the loop 52 may beconnected (as was the loop to the transformer primary Ila). This use ofseparate transformers may facilitate the minimization of length of leadsin the low-impedance loop circuits.

Since the axis of the loop is very approximately parallel with thestrings, the magnetic fields which the strings are caused to have arepreferably longitudinal of the strings. Such a field is most simplyprovided for each string by permanently magnetizing it, particularly inthe region adjacent the loop. Means and methods for magnetizing thestring, being themselves known in the art and forming no necessarypermanent part of the instrument, need not be specifically describedherein. It will be understood that as any one of the strings is vibratedtoward and away from the loop-for example as a result of its beingexcited by the action Athe influence of its magnetic field on the lcopis osclllatorily varied in accordance with the frequency and wave formof the string portion adjacent the loop, thereby generating in the loopcircuit a corresponding alternating voltage representing the stringvibration. The voltages so generated by as many strings as may besimultaneously vibrated, superimposed on each-other, are stepped up bythe transformers 56 and 51, and appear in their magnified amplitude inthe circuit 58 in which the secondaries 36b and 51b of thosetransformers are both connected.

The circuit 58 forms a load circuit for the utilization of thetranslated oscillatory voltages. It may comprise a cascade of electricalamplifying and control means and electro-acoustic translating means. InFigure 4 it has been shown as comprising for example amplifier portion34, tone control 35, amplifier portion'36, volume control 31 (controlledfor example by pedal 10), amplifier portion 38, and electro-a'coustictrans lating means 39 and 40. The translating means 39 may be a"low-frequency" sound radiatore. g., a loudspeaker'which, while it mayhave a response at all audio frequencies, is particularly It may beforwardly directed, and if desired may be baffled by the removable frontcover member ll, suitably apertured for this purpose. The relativelysmaller high-frequency speaker 40 may be secured to the plate I in anyconvenient manner, likewise preferably forwardly directed to emit soundthrough the front cover member i i, which may be further suitablyapertured for this loudspeaker. the invention contemplates thedisposition of the low-frequency radiator or loudspeaker relativelyadjacent the low-note extremity, and the disposition of thehigh-frequency radiator or loudspeaker relatively adjacent the high-noteex- "t'remity, of the keyboard and instrument, and the speakers haveaccordingly been so illustrated. I have found this arrangement markedlyto enhance the naturalness of pianistic performance by an instrument ofthis type.

In Figures 5 and 6 I show another embodiment of my invention, whereinthe conductive circuit may be in the form of a coil whose axis extendstransversely of the strings, peripheral portions of the coil beingadjacent the strings A preferred embodiment of to be osclllatorilyapproached andreceded from I by the strings in their vibrations. Purelyby way of example, I have shown this construction embodied in aninstrument of the grand-piano type. Thus in these figures there will beseen the rear portion 60 of a metallic plate. or frame, which mayfurther include the front portion Cl and the capo" or cross-bar portion82 as seen in Figure 6. Underneath the front plate portion 6|appears'the wrest-plank 63; tuning pins 84 may extend downwardly intothe wrest plank through oversize holes in the plate portion 0|. From thetuning pins to respective hitch pins 65 in the rear plate portion 60there may be strung the respective tuned strings 66 of the instrument.These may pass over ledge la on front plate portion ll, under the capo82, over a bridge 61, and over a ledge 600 on rear plate portion 60.

The strings are caused to engage the bridge; and

while this may be done by respective pairs of bridge pins as in theinstrument-of earlier fig-- ures, I have by way of alternative exampleshown the forward pin of each pair replaced by a grooved screw 63thestring resting in the circumferential groove 68a therein, so thatadjustment of the screw serves to raise and lower the string (asdisclosed in Patent No. 1,915,859 to Miessner et al.). The bridge 61 hasbeen shown as vibratilly supported, for example to the usual vibratileribs 69. For effecting and controlling the string vibrations I haveshown as A, partially schematically, a typical grand-piano action. Thismay include the pivoted keys HI, hammers II, and action mechanismschematically indicated as I2 interposed therebetween. In theillustration of this embodiment there has been shown, by way of example,the employment tion, the coil being arranged in an appropriatelongitudinal configuration; the coil 15 has been illustrated aspositioned underneath string portions relatively near the bridge 61. Thecoil may be mounted sothat its top side is slightly spaced larlyarranged to those of the utilization circuit 53 already described, ithas for simplicity been shown as comprising the amplifier portion 3|,volume control 82, amplifier portion 83 and loudspeaker in. v

In the various embodiments of my invention there may of course beemployed a plurality of the mechanico-electric translating means, orconductive fcircuits, respectively associated with different portions ofthe strings, with differential phase and/or. amplitude control overtheir respective, outputs (as disclosed for mechanicoelectrictranslating devices broadly in Patent No. 1,906,607 to Jacobs). I haveillustrated this availability in the instrument of Figures 54) by theshowing of a second coil 16 arranged similarly to the coil 15 exceptingthat it is underneath a more forward portion of each string. To providethe differential control over respective outputs of the two coils, I mayconnect them across respective potentiometers I1 and 18, the fixedmid-points of the potentiometers being connected together, and theirvariable contacts being connected to the input of the amplifier portionllthe impedance of this input, and the impedances of the potentiometers,being of course preferably chosen at values appropriate to theimpedances of the coils I5 and I8.

With the conductive circuit arrangement illustrated in Figures56particularly when, as illustrated, the coil axis is obliquely (asdistinguished from right-angularly) transverse to the strings-apermanent magnetization of the strings may be employed as in the case ofthe embodiment of earlier figures. But since the coil axis is mor nearlyat right angles to the strings than parallel thereto (and may be quiteat right angles to certain strings of the instrument) I prefer that themagnetic fields of the strings extend at right angles to-for example, inplanes transverse totheir longitudinal directions. Such a field for astring may be created by the passage of a current longitudinally throughthe string; and in Figure 6 I have schematically illustrated anarrangement for such current passage.

This arrangement may comprise a current source 05, one ,terminal ofwhich may be electrically connected with the rear plate portion 00 andtherethrough to the rear extremities of all the strings. The otherterminal of the source ll may be connected to all the tuning pins 00 (i.e., to the front extremities of the strings). For purposes hereinafterapparent it may be desirable that these connections to the front stringextremities be individual to the several-strings; and such individualconnections may for example be made through individual switches 80. (Topreserve the individuality of the front-extremity connect ons, thestrings in passing over the ledge 0 la and under the capo 02 may beinsulated from those respective elements by thin curved pieces ofinsulation 6 b and 621) respectively. seen in Figure 6). It will beunderstood that with the switches 0! closed, currents will becontinuously passed through the strings: to limit or to equalize thesecurrents there may if desired be employed, for example in series withthe switches 00, respective resistances 81. Th magnetic fieldsabovementioned will be continuously maintained: the voltages translatedfrom the strings, and the sounds translated therefrom by theelectro-acoustic translating means, will have envelopes (oramplitude-time characteristics) correspondingthroughout to those of thestring vibrations; and, h an instrument of the disclosed t the toneswill accordingly be of initially percussive, pianistic nature.

The creation of magnetic fields by current passage, however, may beemployed to permit the variation of the envelopes of the electricoscillations and output tones from those of the string vibrationsrespectively giving rise thereto. Thus the current passage through eachstring may be controlled in predetermined relationship to the excitationof that string; and by way of specific example, the current passage maybe initiated as or just after the instant of beginning of the stringvibration (e. g., of the hammer striking the string), so that thepercussive initial peak of the vibration envelope is eliminated from theenvelope of the electric oscillations and the output tone.

There have been disclosed in prior patents to me or to me and another(e. g., 1,915,860; 1,915,-

" brational frequencies.

859; 2,071,649) and in a copending application of mine (Serial No.208,357, filed May 17, 1938, now Patent No. 2,233,058) variousvariable-resistance arrangements for controlling (by control ofsensitizing voltage, oscillation output, or the like) the translationfrom a string or other vibrator in predetermined relationship to theexcitation thereof; and a variable-resistance arrangement basicallysimilar to one of these may for example be employed for the control ofthe current through the string. By way of example I have shown in Figure6 a respective variable resistance, designated generally as 95,positioned underneath the front portion of each key I0 for operationthereby. Specifically each variable resistance may comprise a pile ofcarbon discs 98 retained in a hole 91 in the baseboard 98 of the actionA, and resting on a common conductive plate 00 which extendstransversely across the bottom of the baseboard and may form a commonconnection to one side of all the resistances 05. For contact with thetop of each pile there may be provided a respective contact button I00,carried for example on the bottom of the front portion of a forwardlyextending leaf spring IOI whose rear extremity i secured to the top ofthe baseboard 98. Extending downwardly from the bottom of each key 10,above the forward extremity of the respective spring IIll, may be anadjustable screw I02.

Each spring I 0| may be biased so that normally there is little or nopressure of the button I00 on the carbon disc pile; accordingly thnormal value of each resistance 95 will be very high or infinite. In thedownstroke of the key, however, the screw I02 will impinge on the springand force the button to compress, and lower the resistance of, thecarbon disc pile-the structure serving as a downstop for the key. Thevariable resistances 95 may be connected across the respective switches86 and resistances 01 abovementioned, becoming effectively substitutedtherefor when those switche are open. Each screw I02 may be adjusted sothat the respective key will have its normal downstroke, and so that theresistance of the respective carbon disc pile will still be high (andthe current through the respective string therefore negli ible) at theinstant of contact of the respective hammer with the respectivestringthe resistance reduction, and consequent rise of current fiowthrough the string, occurring wholly or principally after that contact.

In its simplest embodiment the current source 05 may of course be asource of direct current. the magnetic fields of the strings accordinglybeing steady (as distinguished from alternating) fields. The source mayalternatively, however, be a high (over-audible) frequency alternatingcurrent source. In the latter case the magnetic fields of the stringswill b high-frequency alternating fields, and the electric oscillationsin the coils I5 and I8 will be high-frequency oscillations modulated atthe string vi- In this case the amplifier portion 8| may be operated asa demodulator, so that the oscillations passing to the loudspeaker willbe the modulating frequencie and thus will again represent the stringvibrational frequencies.

The choice of the type oi source 85 may of course be made independentlyof whether the current fiow through the string'is to be varied, as byresistance 95, or maintained steady. It may be observed, however, thatwhen the source I! is a direct current source, there may if desired beassociated with each variable resistance Ql a filtering or time-delaymeans, to insure a smoothness and a desired degree of graduality in therise of the string currents and output tones. Such means have been quiteschematically illustrated in Figure 6 as condensers 94 respectivelyshunted across the variable resistances 8i.

The coils II and I8 may if desired be constructed without magneticcores, .the cylindrical space therewithin being either open or filledwith a generally cylindrical member (such members appearing as 150 and160 respectively) which in this case may be of insulating material andmay act simply as a mandrel for the coil. The members 15c and 16c may,however, constitute magnetic cores for the coils, in which case they maybe of appropriate magnetic material in appropriate form. The latterarrangement, in view of an increasing effect on the efllciency of thetranslation by the coils, is usually to be preferred.

The illustration of the instrument of Figures -6 has been presented infractional form, since there will be obvious from the earlier embodimentmanners in which'the invention will be carried out in a completeinstrument. llt will be understood that while I have shown various morespecific features of my invention in different groupings in the twoembodiments, this has been primarily for purposes of illustration andexplanation rather than limitative; many of those features will be seento be mutually interchangeable. Again, it will be understood that whileIv have chosen instruments of the piano type for the illustration of myinvention,- various of its features are obviously applicable to othertypes of instruments. Finally, it will be understood that in generalmany modifications of the instruments shown and described will readilysuggest themselves to those skilled in the art, and that these will notnecessarily constitute departures from the spirit of the invention, orfrom its scope as expressed in the appended claims.

I claim:

l. In a musical instrument including a load circuit for the utilizationof sound-representing side for adjusting the spacing of the same fromthe vibrators.

4. In a musical instrument including a load circult for the utilizationof sound representing oscillations: the combination of a plurality ofvariously tuned vibrators having magnetic fields tors to be approachedand receded from by vibrators and thereby magnetically influenced at thevibrator vibrational frequencies.

5. In a musical instrument including a load circuit for the utilizationof sound-representing electric oscillations: the combination of aplurality of variously tuned strings disposed essenoscillations: thecombination of a plurality of variously tuned vibrators having magneticfields and disposed essentially in a plane; and a closed conductivecircuit electrically feeding said load circuit, extending transverselyof said vibrators with operatively substantially uniform structurecontinuously throughout that extent and having portions adjacent to saidvibrators to be approached and receded from by the vibrators and therebymagnetically influenced at the vibrator vibrational frequencies.

2. In a musical instrument including a load circuit'for the utilizationof sound-representing oscillations: the combination of a plurality ofvariously tuned vibrators having longitudinal magnetic fields anddisposed essentially in a plane; and a conductive loop electricallyfeeding said load circuit, extending transversely of said vibrators withoperatively substantially uniform structure continuously throughout thatextent and having one side adjacent to said vibrators to be approachedand receded from by the vibrators and thereby magnetically influenced atthe vibrator vibrational frequencies.

3. The combination according to claim 2, wherein the loop comprises aheavy conductor of relatively soft material, and further including atially in a plane; means for passing currents longitudinally throughsaid strings, whereby .to create magnetic fields about said strings; andan elongated coil electrically feeding said load circuit, having an axisextending transversely of said strings and having peripheral portionsadjacent thereto to be approached and receded from by the strings andthereby magnetically influenced at the string vibrational frequencies.

6. In a musical instrument including a load circuit for the utilizationof sound-representing electric oscillations: the combination of aplurality of variously tuned strings disposed essentially in a plane; aplurality of means respectively associated with different-frequencystrings for exciting the same; means, operatively associated with eachexciting means, for passing current through the excited strings inpredetermined time relationship to their excitation; and a closedconductive circuit electrically feeding said load circuit, extendingtransversely of said strings and having portions adjacent thereto to beapproached and receded from by the strings and thereby magneticallyinfluenced at the string vibrational frequencies.

7. In a musical instrument including a load circuit for the demodulationand utilization of electric oscillations modulated at sound-representingfrequencies: the combination of a plurality of variously tuned stringsdisposed essentially in a plane; means for passing high-frequencycurrents through said strings, whereby to create high-frequency magneticfields about said strings; and a closed conductive circuit electricallyfeeding said load circuit, extending transversely of said strings andhaving portions adjacent thereto to be approached and receded from bythe strings, whereby there is induced in said conductive circuit ahigh-frequency voltage modulated at the string vibrational frequencies.

8. In a musical instrument including a load circuit for the utilizationof sound-representing electric oscillations: the combination ofaplurality of variously tuned vibrators having magnetic fields anddisposed essentially in a plane; and a plurality of closed conductivecircuits electrically feeding said load circuit, each conductive circuitextending transversely of said vibrators with operatively substantiallyuniform structure continuously throughout that extent and havingportions adjacent to respective longitudinal regions of said vibratorsto be approached and receded from by said vibrator regions and therebymagnetically influenced in accordance with the vibrations of, thosevibrator regions.

9 The combination according to claim 8, further including means forvarying the relative amplitudes of oscillations fed by the respectiveconductive circuits to said load circuit.

10. The combination according to claim 8, further including means forvarying the relative phases of oscillations fed by the respectiveconductive circuits to said load circuit.

11. In a musical instrument including a load circuit for the utilimtionof sound-representing electric oscillations: the combination of a tunedstring; means for exciting said string; means operatively associatedwith said exciting means for passing a current longitudinally throughsaid string in predetermined time relationship to its excitation; and aconductive circuit electrically feeding said load circuit, having aportion adjacent to said string to be approached and receded from bysaid string and thereby magnetically influenced at the stringvibrational frequencies.

12. In a musical instrument including a load circuit for the utilizationof sound-representing electric oscillations: the combination of a tunedstring; means for exciting said string; means operatively associatedwith said exciting means for passing a current longitudinally throughsaid string in predetermined time relationship to its excitatio and acoil electrically feeding said load circuit, having an axis transverseto said string and a peripheral portion adjacent thereto to be therebymagnetically influenced at the string vibrational frequencies.

13. In a musical instrument including a load circuit for thedemodulation and utilization of receded from by the string. wherebythere is inassasss duced in said conductive circuit a high-frequencyvoltage modulated at the string vibrational fre- I quencies.

14. In a musical instrument including a load circuit for the utilizationof sound-representing Q for passing a current through said vibrator inpredetermined time relationship to its excitation;

and a conductive circuit electrically feeding said load circuit, havinga portion adjacent to said vibrator to be approached and receded from bysaid vibrator and thereby magnetically influenced at the vibratorvibrational frequencies.

15. In a musical instrument including a load circuit for the utilizationof sound-representing electric oscillations: the combination of a tunedvibrator; means for exciting said vibrator; means operatively associatedwith said exciting means for passing a current longitudinally throughsaid vibrator in predetermined time relationship to its excitation; anda coil electrically feeding said load circuit, having an axis transverseto said vibrator and a peripheral portion adjacent thereto to be therebymagnetically influenced at the vibrator vibrational frequencies.

16. In a musical instrument including a load circuit for thedemodulation and utilization of electric oscillations modulated atsound-representing frequencies: the combination of a tuned vibrator;means for passing a high-frequency current through said vibrator,whereby to create a high-frequency magnetic field about said vibrator;and a closed conductive circuit electrically feeding said load circuit,having a portion adjacent to the vibrator to be approached and recededfrom by the vibrator, whereby there is induced in said conductivecircuit a high-frequency voltage modulated at the vibrator vibrationalfrequencies.

BENJAMIN F'. MESSNER.

